EP3050691A1 - Method for producing a cladding of a connector - Google Patents

Abstract

Method for producing a sheath (1) of a plug part (2) for an electrical and / or optical plug connection and / or a cable (3), wherein the cover (1) is produced by injection molding from a thermoplastic material (4) in an injection mold (5 ) is produced, wherein in addition to the thermoplastic material (4) at least one outgassing propellant (6) and / or at least one gas is injected into the injection mold (5) and gas inclusions (7) in the enclosure (1) are formed.

Description

The following invention relates to a method for producing a covering of a plug part for an electrical and / or optical plug connection and / or a cable, wherein the cover is produced by means of injection molding from a thermoplastic material in an injection mold. Furthermore, the invention also relates to an enclosure of a plug part for an electrical and / or optical plug connection and / or a sheathing of a cable.

In the prior art, it is known to produce casings of the type mentioned above by means of injection molding. These sheaths can z. B. wrap a cable to form a kink protection grommet for the cable. It is just as well known to spray or inject coatings on the basic bodies of plug parts for electrical and / or optical plug connections, so as to form a certain haptic or a certain design or a desired electrical insulation or an impact or corrosion protection on the plug part.

The object of the invention is to improve a generic method to the effect that the envelope by injection molding faster and thus cheaper to produce.

In a method of the abovementioned type, it is provided for this purpose that, in addition to the thermoplastic material, at least one outgassing propellant and / or at least one gas is injected into the injection mold and gas inclusions are formed in the enclosure.

By adding the propellant to the thermoplastic material during injection molding gas pockets are formed in the enclosure by outgassing of the propellant. Alternatively, gas can also be injected directly to the Form gas pockets. As a result, the envelope cools down faster, so that the entire injection molding process can be shortened until the removal of the envelope from the injection mold with respect to the prior art, whereby the envelope is faster and thus cheaper to produce. Another beneficial effect of the invention from an economic point of view lies in the fact that less thermoplastic material is consumed per coating compared to a conventional production method. The envelope is thereby easier on the one hand, on the other hand cheaper to produce.

In the method according to the invention, it is possible by the use of the blowing agent or the gas to work with lower injection pressures and also lower injection temperatures during injection molding. It is a so-called low-pressure injection possible. Preferred embodiments of the method according to the invention provide that the injection pressure is between 5 bar and 40 bar. Preferred ranges of the injection temperature are in the inventive method between 100 ° C and 240 ° C. Both ranges are well below the injection pressures and injection temperatures required in the prior art. For the sake of completeness, it is pointed out that, apart from the measures specifically mentioned here, the injection-molding process for the production of the covering can otherwise be carried out as in the prior art. Since such injection molding processes are known per se in a wide variety of variants in the prior art, it is here omitted to describe them again in detail.

The lower injection pressures and injection temperatures in turn have an economic advantage, since the injection molding machines used can be made smaller and also consumed less energy. In addition to the purely economic advantages, the invention also brings quality benefits. Thus, by the addition of blowing agent and / or gas and the resulting gas inclusions in the envelope, the elasticity of the end product, ie the envelope, can be adjusted very selectively in the desired range. The alternating bending strength of the finished product produced is compared to the state the technique improves. Covers made in accordance with the invention are thus more durable even under heavy mechanical stress and are less likely to break down.

The thermoplastic used in the invention or in other words thermoplastic is basically a plastic that can be deformed in a certain temperature range, this process is reversible, so that the thermoplastic material during injection molding of a solid into a liquid form and then bring it back into a solid state of matter when it cools down. This is known per se, as well as numerous suitable for injection molding thermoplastics or thermoplastic materials. In principle, a wide variety of thermoplastic materials can be used in the course of the invention. Particularly preferred in the course of the invention thermoplastic elastomers or PVC are used. As examples of suitable thermoplastic elastomers may, for. For example, olefin-based thermoplastic elastomers, olefin-based crosslinked thermoplastic elastomers, urethane-based thermoplastic elastomers, thermoplastic polyester elastomers, thermoplastic copolyesters or styrenic block copolymers, and thermoplastic copolyamides may be mentioned.

As stated above, the gas inclusions in the enclosure can be generated in various ways. So it is z. B. possible that an outgassing propellant is injected into the injection mold and formed by outgassing of the propellant, the gas inclusions in the enclosure. Conveniently, this is a chemical blowing agent, ie a chemical substance whose decomposition gas is split off or released. Preferably, the blowing agent and in particular the chemical blowing agent for inducing the outgassing process is thermally activated. In principle, however, a chemical activation of the blowing agent is possible, for. B. by bringing at least two components together so that they ignite the outgassing process by chemical interactions. Particularly preferred variants provide that the propellant for inducing the Outgassing process, preferably in the injection mold, is thermally activated. The thermoplastic material and / or the blowing agent may, for example, before the beginning of the injection molding process. B. in granular form. As a blowing agent and liquids with a correspondingly low evaporation temperature can be used. These can also be thermally activated, that is, they can be used to evaporate and thus to generate gas. Alternative embodiments of the invention may also provide that the thermoplastic material and the blowing agent are not premixed but injected simultaneously or successively into the injection mold. Instead of the blowing agent, it is also conceivable to inject at least one gas directly into the injection mold in addition to the thermoplastic material. Suitable gases for this purpose are, for example, nitrogen (N ₂ ) or carbon dioxide (CO ₂ ). For the sake of completeness, it is pointed out that both the thermoplastic material and the propellant, as well as the gases, may in each case be a substance or a material but also in each case a mixture of a plurality of materials, blowing agents or gases.

Suitable propellants and also gases are known per se in the prior art. Examples of suitable granular blowing agents are available on the market under the trade name Hydrocerol. As a liquid propellant z. As gasoline or water can be used. The blowing agents can consist of both organic and inorganic compounds.

Conveniently, the gas inclusions are formed in the form of self-contained gas bubbles or pores. One could therefore also speak of a closed porosity. But it is also the formation of an open porosity so interconnected gas bubbles or pores conceivable. Preferably, the admixed amount of propellant and / or gas or propellant gas is adjusted so that the porosity caused by the gas inclusions in the final product, so the envelope is in a range between 5% and 40%. In other words, the gas inclusions then have a volume fraction of preferably 5 to 40% of the end product or of the casing. However, this volume fraction of the gas inclusions or this porosity can also reach values of up to 60% or even up to 80%. The Gas inclusions are arranged in the finished enclosure in a matrix consisting of the thermoplastic material. In other words, the gas inclusions form a porosity in the thermoplastic material of the finished casing. One could also speak of a foaming of the thermoplastic material.

Preferred embodiments of the invention provide that the blowing agent, based on the state before outgassing, in a proportion of 0.5% to 5%, preferably from 1.5% to 2.5%, of the total mass of the thermoplastic material and the blowing agent is injected into the injection mold.

In the method according to the invention, the casing can be injection-molded onto a main body of the plug part and / or on the cable. In this variant, one can also speak of an encapsulation of the main body and / or the cable. For this purpose, as is known, the base body and / or the cable is introduced into the injection mold before the injection process. When the injection mold is closed, the injected thermoplastic material is then injected directly onto the base body and / or the cable. An alternative of the method according to the invention can also be to initially produce the envelope in the injection mold by means of injection molding and then to attach it to or on the base body of the plug part and / or the cable.

In addition to the method, the envelope of a plug part for an electrical and / or optical plug connection and / or a cable is the subject of the invention, wherein it is provided that the cover has thermoplastic material and in the enclosure gas inclusions in the thermoplastic material are present. Such wraps can be produced by the method according to the invention. The porosity caused by the gas inclusions in the casing is, as indicated above, favorably in a range between 5% and 40%. Preferably, the gas pockets are formed as a plurality of gas bubbles or pores distributed over the envelope. Conveniently, the gas inclusions or pores are substantially uniform distributed over the wrapping. The gas inclusions favorably have a diameter between 10μm and 1.5mm. The diameter of each of the largest diameter of the respective pore or the respective gas bubble is called. The enclosure of the invention may, for. B. be a kink protection grommet for the cable. It is a sheath, which is mounted in the area on the cable and possibly also on the plug part, where the cable is guided into the plug part. The kink protection grommet supports the cable where it is led out of the plug part, so that kinking or tearing off the cable from the plug part is prevented to the greatest possible extent in this area. But an enclosure according to the invention may also be a so-called overmold for a main body of the plug part. It is a coating of this body. In the main body may be z. B. to act made of metal or plastic housing of the connector part. Of course, the wrapper can also be a combination of anti-kink sleeve and overmold. It can thus also have an area which is a kink protection grommet and have a different area, which is an overmold, wherein these two areas can hang integrally together.

For the sake of completeness, it is pointed out that the finished cover according to the invention can surround the plug part or its base body and / or the cable completely peripherally closed, but need not. The enclosure can also be formed only on partial areas and in particular not circumferentially closed on the plug part, the base body and / or the cable or be.

Fig. 1

eine erfindungsgemäß ausgebildete Umhüllung in Form einer Knickschutztülle in einer Seitenansicht;

Fig. 2

einen schematisierten Längsschnitt durch Fig. 1 und damit durch die Knickschutztülle;

Fig. 3

eine schematisierte Darstellung zum erfindungsgemäßen Herstellungsverfahren des ersten Ausführungsbeispiels mittels Spritzguss;

Fig. 4

den Bereich A aus Fig. 3;

Fig. 5

ein zweites Ausführungsbeispiel einer erfindungsgemäßen Umhüllung, welche sowohl ein Overmold für einen Grundkörper des Steckerteils als auch eine Knickschutztülle ausbildet;

Fig. 6

einen schematisierten Längsschnitt durch Fig. 5 und

Fig. 7

wiederum eine schematisierte Darstellung zum Herstellungsverfahren mittels Spritzguss zu der Ausführungsvariante gemäß der Fig. 5 und 6.

Further features and details of preferred embodiments of the invention will be explained with reference to the following description of the figures. Show it:

Fig. 1

an inventively formed enclosure in the form of a kink protection grommet in a side view;

Fig. 2

a schematic longitudinal section through Fig. 1 and thus by the anti-kink sleeve;

Fig. 3

a schematic representation of the manufacturing method according to the invention of the first embodiment by injection molding;

Fig. 4

the area A off Fig. 3 ;

Fig. 5

A second embodiment of an enclosure according to the invention, which forms both an overmold for a main body of the male part and a kink protection grommet;

Fig. 6

a schematic longitudinal section through Fig. 5 and

Fig. 7

Again, a schematic representation of the manufacturing process by injection molding to the embodiment according to the FIGS. 5 and 6 ,

Fig. 1 shows a side view of an enclosure 1 according to the invention in the form of a kink protection sleeve 16 for the cable 3. Both the cable 3 and the main body 8 of the connector part 2 are shown only highly schematized. This is especially true for the longitudinal section, which in Fig. 2 you can see. Such a bend protection sleeve 16 with the plug part 2 attached thereto can, for. Example, in a power cable 3, which leads into a drill, a grinder or other implement, are used to protect the cable 3 from being demolished or bent in the area where it comes out of the housing of the machine. In the illustrated embodiment, the plug part 2 is provided for a detachable plug-in connection with a arranged in the working device, not shown here socket. Of course this is just an example. The anti-kink sleeve 16 could just as well be fixed to the housing of the machine.

In the longitudinal section according to Fig. 2 are the gas inclusions 7, which extend finely distributed over the entire enclosure 1 or bend protection sleeve 16, shown schematically. The gas inclusions 7 are surrounded by a matrix of the thermoplastic material 4.

Fig. 3 shows very schematically the injection mold 5 and the injection unit 11 of an injection molding machine, with which the inventive method for producing the envelope 1 of the connector part 2 can be performed. A detailed description of a corresponding injection molding machine is dispensed with, since this is known per se in the prior art. The injection mold 5 has, as is known, two mold halves 9. These enclose in their closed position shown here together a mold cavity 18, which thus defines the outer contour and shape of the end product here of the enclosure 1. Before the actual injection molding process, the main body 8 and the cable 3 fastened therein are inserted into the mold cavity 18 when the injection mold 5 is open. Subsequently, the mold halves 9 are closed and pressed together with the contact pressure required for the injection molding process. The starting material, in this example consisting of a mixture of thermoplastic material 4 and blowing agent 6, is introduced into the filling funnel 19 of the injection unit 11. In Fig. 4 is the area A off Fig. 3 schematized and enlarged shown. It can be seen that in the starting material of this embodiment, both the thermoplastic material 4 and the propellant 6 are present in each case as granules. In the illustrated embodiment, the injection unit 11, as known per se, a screw 12, which is rotatably mounted in the injection tube 13 about its longitudinal direction and displaceable in the longitudinal direction. With the tip 14 of the injection unit 11, this opens into the, provided in one of the mold halves 9 injection channel 15th

The pretreatment of the thermoplastic material 4 in the injection unit 11, as well as the injection process itself, in principle take place once known per se as in the prior art. It can thus be provided that by rotating the screw 12, the material mixture consisting of thermoplastic material 4 and propellant 6 is conveyed from the reservoir 19 into the injection tube 13 and transported there in the direction of the tip 14. In this transport towards the tip 14, the thermoplastic material 4, optionally with the aid of not shown here, but known per se heating elements on or in the injection tube 13, liquefied. For the injection process then collects a corresponding amount For injection itself, the screw 12 is displaced in its longitudinal direction in the direction of the tip 14, so that the material accumulated in the tip 14 via the Anspritzkanäle 15 in the mold cavity 18 is injected and this fills. When the propellant 6 mixed under the thermoplastic material 4 begins to outgas, it can be controlled via a corresponding temperature profile if it is a thermally activatable propellant. So it is z. B. conceivable that even in the injection tube 13 of the outgassing process begins when there already appropriate temperatures are reached. However, it is equally conceivable that the propellant 6 is first injected into the mold cavity 18 and is then brought to a temperature by means of heating devices arranged there, not explicitly shown here, which leads to the thermal activation and thus to outgassing of the propellant 6. It would also be possible to heat the injection channels 15 in order to bring about a corresponding thermal activation.

Deviating from this embodiment, of course, other and also a plurality of injection units 11 can be used to inject the thermoplastic material 4 and the blowing agent 6 or the thermoplastic material 4 and a propellant gas in the mold cavity in the inventive method. In particular, when injecting gas or propellant gas instead of propellant 6, a separate injection unit 11 may be provided for the gas or propellant to introduce the gas or propellant into the mold cavity 18. Equally, it would be conceivable that the gas or propellant gas is added only in the region of the tip 14 to the thermoplastic material 4 which has already been melted there. A corresponding injection of propellant 6 at this point would be conceivable.

Instead of realized here, known per se screw 12 could be provided longitudinally displaceable for the injection process in the injection tube 13 and a simple piston. All known in the art, suitable per se injection and injection molding machines can be in accordance with adapted type and be used for the method. In the Fig. 3 shown variant is just an example.

The Fig. 5 to 7 serve to illustrate a second example according to the invention of a casing 1 and its production by injection molding. In the in the Fig. 5 in a plan view and in Fig. 6 in a longitudinal section shown connector part 2 is a so-called cable connector, in which a cable 3 is guided into a base body 8 and a housing of the connector part 2. Such connector parts 2 can be used both for signal and for energy transmission. You can optical and / or electrical connectors by mating with at least one corresponding, not shown here, further connector part. This second or further plug part can in turn be a cable plug or a device socket. The plug contacts 20 in the main body 8, which serve the electrical and / or optical signal transmission and / or energy transfer, are shown here only highly schematic and can, as in the prior art known to be executed in a variety of embodiments.

In this second exemplary embodiment, the covering 1 comprises both an area which forms a bend protection sleeve 16 and a region which forms an overmold 17 over the base body 8 or the housing of the plug part 2. These two areas, so the overmold 17 and the anti-kink sleeve 16 are injection-molded together in this embodiment and are thus made in one piece. This is also good to see in longitudinal section of FIG. 16. The gas inclusions 7, which are arranged in a finely distributed manner over the entire casing 1 in the matrix-forming thermoplastic material 4, are again shown schematically there. Fig. 7 again shows the process of the invention analogously to illustrate Fig. 3 schematized components of an injection molding machine. For their explanation as well as to explain the injection molding process and the possible alternatives to the description Fig. 3 directed. All that has been said here can be applied analogously to produce the envelope 1 by means of injection molding. Also the section A from Fig. 7 corresponds to Fig. 4 , that is, the mixture 10 shown there from the granular thermoplastic material 4 and the granular blowing agent 6 mixed there.

Legend to the reference numbers:

1

wrapping

2

plug part

3

electric wire

4

thermoplastic material

5

injection mold

6

propellant

7

gas inclusion

8th

body

9

mold

10

mixture

11

An injection unit

12

slug

13

Injection pipe

14

syringe

15

injection channel

16

bend relief

17

overmold

18

mold cavity

19

reservoir

20

plug contact

Claims (10)

Method for producing a sheath (1) of a plug part (2) for an electrical and / or optical plug connection and / or a cable (3), wherein the cover (1) is produced by injection molding from a thermoplastic material (4) in an injection mold (5 ), characterized in that in addition to the thermoplastic material (4) at least one outgassing propellant (6) and / or at least one gas is injected into the injection mold (5) and gas inclusions (7) formed in the enclosure (1) become. A method according to claim 1, characterized in that the blowing agent (6) for inducing the outgassing process, preferably in the injection mold (5), is thermally activated. A method according to claim 1 or 2, characterized in that the blowing agent (6) is added to the thermoplastic material (4) prior to injection and the mixture (10) thus produced from the thermoplastic material (4) and the blowing agent (6) into the Injection mold (5) is injected. Method according to one of claims 1 to 3, characterized in that the sheath (1) to a base body (8) of the plug part (2) and / or to the cable (3) is molded, or that the sheath (1) initially in the injection mold (5) is produced by means of injection molding and then attached to or on the base body (8) of the plug part (2) and / or the cable (3). Method according to one of claims 1 to 4, characterized in that the blowing agent (6), based on the state before outgassing, in a proportion of 0.5% to 5%, preferably from 1.5% to 2.5% , is injected at the total mass of the thermoplastic material (4) and the blowing agent (6) into the injection mold (5). Method according to one of claims 1 to 5, characterized in that the injection pressure in a range between 5 bar and 40 bar and / or the injection temperature is in a range between 180 ° C and 240 ° C or lie. Enclosure (1) of a plug part (2) for an electrical and / or optical plug connection and / or a cable (3), in particular produced by a method according to one of claims 1 to 6, wherein the cover (1) comprises thermoplastic material (4). characterized in that in the sheath (1) gas inclusions (7) in the thermoplastic material (4) are present. A casing (1) according to claim 7, characterized in that the porosity of the casing (1) caused by the gas inclusions (7) is in a range between 5% and 40%. Enclosure (1) according to claim 7 or 8, characterized in that the gas inclusions (7) as a plurality of over the sheath (1) distributed gas bubbles are formed and / or have a diameter between 10μm and 1.5mm. Enclosure (1) according to one of claims 7 to 9, characterized in that the sheath (1) has a kink protection sleeve (16) for the cable (3) and / or an overmold (17) for a base body (8) of the connector part (2 ).

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